"Teacher, which is the great commandment in the Law?" And [Jesus] said to him, "You shall love the Lord your God with all your heart and with all your soul and with all your mind. This is the great and first commandment." (Matthew 22:36-38 ESV)
"I will suggest that loving God with the mind means that our thinking is wholly engaged to do all it can to awaken and express the heartfelt fullness of treasuring God above all things. Treasuring God is the essence of loving him, and the mind serves this love by comprehending (imperfectly and partially, but truly) the truth and beauty and worth of the Treasure."
(John Piper, Think: The Life of the Mind and the Love of God.)